271 lines
6.3 KiB
C
271 lines
6.3 KiB
C
/*
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* cpuidle-powernv - idle state cpuidle driver.
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* Adapted from drivers/cpuidle/cpuidle-pseries
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/moduleparam.h>
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#include <linux/cpuidle.h>
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#include <linux/cpu.h>
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#include <linux/notifier.h>
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#include <linux/clockchips.h>
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#include <linux/of.h>
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#include <asm/machdep.h>
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#include <asm/firmware.h>
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#include <asm/runlatch.h>
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/* Flags and constants used in PowerNV platform */
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#define MAX_POWERNV_IDLE_STATES 8
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#define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */
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#define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */
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struct cpuidle_driver powernv_idle_driver = {
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.name = "powernv_idle",
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.owner = THIS_MODULE,
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};
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static int max_idle_state;
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static struct cpuidle_state *cpuidle_state_table;
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static int snooze_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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local_irq_enable();
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set_thread_flag(TIF_POLLING_NRFLAG);
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ppc64_runlatch_off();
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while (!need_resched()) {
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HMT_low();
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HMT_very_low();
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}
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HMT_medium();
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ppc64_runlatch_on();
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clear_thread_flag(TIF_POLLING_NRFLAG);
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smp_mb();
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return index;
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}
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static int nap_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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ppc64_runlatch_off();
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power7_idle();
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ppc64_runlatch_on();
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return index;
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}
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static int fastsleep_loop(struct cpuidle_device *dev,
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struct cpuidle_driver *drv,
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int index)
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{
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unsigned long old_lpcr = mfspr(SPRN_LPCR);
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unsigned long new_lpcr;
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if (unlikely(system_state < SYSTEM_RUNNING))
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return index;
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new_lpcr = old_lpcr;
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/* Do not exit powersave upon decrementer as we've setup the timer
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* offload.
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*/
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new_lpcr &= ~LPCR_PECE1;
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mtspr(SPRN_LPCR, new_lpcr);
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power7_sleep();
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mtspr(SPRN_LPCR, old_lpcr);
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return index;
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}
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/*
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* States for dedicated partition case.
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*/
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static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
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{ /* Snooze */
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.name = "snooze",
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.desc = "snooze",
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.exit_latency = 0,
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.target_residency = 0,
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.enter = &snooze_loop },
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};
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static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
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unsigned long action, void *hcpu)
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{
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int hotcpu = (unsigned long)hcpu;
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struct cpuidle_device *dev =
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per_cpu(cpuidle_devices, hotcpu);
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if (dev && cpuidle_get_driver()) {
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switch (action) {
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case CPU_ONLINE:
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case CPU_ONLINE_FROZEN:
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cpuidle_pause_and_lock();
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cpuidle_enable_device(dev);
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cpuidle_resume_and_unlock();
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break;
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case CPU_DEAD:
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case CPU_DEAD_FROZEN:
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cpuidle_pause_and_lock();
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cpuidle_disable_device(dev);
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cpuidle_resume_and_unlock();
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break;
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default:
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return NOTIFY_DONE;
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}
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}
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return NOTIFY_OK;
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}
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static struct notifier_block setup_hotplug_notifier = {
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.notifier_call = powernv_cpuidle_add_cpu_notifier,
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};
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/*
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* powernv_cpuidle_driver_init()
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*/
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static int powernv_cpuidle_driver_init(void)
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{
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int idle_state;
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struct cpuidle_driver *drv = &powernv_idle_driver;
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drv->state_count = 0;
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for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
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/* Is the state not enabled? */
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if (cpuidle_state_table[idle_state].enter == NULL)
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continue;
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drv->states[drv->state_count] = /* structure copy */
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cpuidle_state_table[idle_state];
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drv->state_count += 1;
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}
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return 0;
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}
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static int powernv_add_idle_states(void)
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{
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struct device_node *power_mgt;
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int nr_idle_states = 1; /* Snooze */
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int dt_idle_states;
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const __be32 *idle_state_flags;
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const __be32 *idle_state_latency;
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u32 len_flags, flags, latency_ns;
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int i;
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/* Currently we have snooze statically defined */
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power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
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if (!power_mgt) {
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pr_warn("opal: PowerMgmt Node not found\n");
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return nr_idle_states;
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}
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idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
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if (!idle_state_flags) {
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pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
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return nr_idle_states;
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}
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idle_state_latency = of_get_property(power_mgt,
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"ibm,cpu-idle-state-latencies-ns", NULL);
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if (!idle_state_latency) {
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pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n");
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return nr_idle_states;
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}
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dt_idle_states = len_flags / sizeof(u32);
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for (i = 0; i < dt_idle_states; i++) {
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flags = be32_to_cpu(idle_state_flags[i]);
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/* Cpuidle accepts exit_latency in us and we estimate
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* target residency to be 10x exit_latency
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*/
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latency_ns = be32_to_cpu(idle_state_latency[i]);
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if (flags & IDLE_USE_INST_NAP) {
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/* Add NAP state */
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strcpy(powernv_states[nr_idle_states].name, "Nap");
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strcpy(powernv_states[nr_idle_states].desc, "Nap");
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powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
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powernv_states[nr_idle_states].exit_latency =
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((unsigned int)latency_ns) / 1000;
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powernv_states[nr_idle_states].target_residency =
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((unsigned int)latency_ns / 100);
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powernv_states[nr_idle_states].enter = &nap_loop;
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nr_idle_states++;
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}
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if (flags & IDLE_USE_INST_SLEEP) {
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/* Add FASTSLEEP state */
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strcpy(powernv_states[nr_idle_states].name, "FastSleep");
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strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
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powernv_states[nr_idle_states].flags =
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CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP;
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powernv_states[nr_idle_states].exit_latency =
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((unsigned int)latency_ns) / 1000;
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powernv_states[nr_idle_states].target_residency =
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((unsigned int)latency_ns / 100);
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powernv_states[nr_idle_states].enter = &fastsleep_loop;
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nr_idle_states++;
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}
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}
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return nr_idle_states;
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}
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/*
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* powernv_idle_probe()
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* Choose state table for shared versus dedicated partition
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*/
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static int powernv_idle_probe(void)
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{
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if (cpuidle_disable != IDLE_NO_OVERRIDE)
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return -ENODEV;
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if (firmware_has_feature(FW_FEATURE_OPALv3)) {
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cpuidle_state_table = powernv_states;
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/* Device tree can indicate more idle states */
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max_idle_state = powernv_add_idle_states();
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} else
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return -ENODEV;
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return 0;
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}
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static int __init powernv_processor_idle_init(void)
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{
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int retval;
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retval = powernv_idle_probe();
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if (retval)
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return retval;
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powernv_cpuidle_driver_init();
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retval = cpuidle_register(&powernv_idle_driver, NULL);
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if (retval) {
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printk(KERN_DEBUG "Registration of powernv driver failed.\n");
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return retval;
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}
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register_cpu_notifier(&setup_hotplug_notifier);
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printk(KERN_DEBUG "powernv_idle_driver registered\n");
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return 0;
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}
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device_initcall(powernv_processor_idle_init);
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